What would you expect to be different for non English-speaking countries? And if there are such differences, which is quite probable, won't differences of a similar kind exist in turn between non English-speaking countries?

I am also unaware of any comprehensive guide for promoting EA, although there are guides on aspects of what can be considered promoting EA, like on establishing chapters and giving talks, of course.

If you are looking for specific advice, I suggest you talk to EA organizations like .impact or EA Outreach.

In the last years some research has been done on movement building and organizing. The conclusion of "Hahrie Han (2015): How Organisations Develop Activists" is that successful organisations don't rely solely on attracting people that are already motivated and skilled but also on actively developing their activists by coaching and mentoring them from the bottom up and moving them up "the activist ladder". Instead of organizing events the leaders in high engagement organisations "organize organizers". The activist ladder may contain steps like I = occasional activist, II = typical activist, III = dedicated activist etc. I think a discussion whether we should concentrate on step I, II or III will remain inconclusive due to the high uncertainty of the parameters. It seems way more important to establish a (semi-)formal system, a pyramid of leaders who mainly engage in coaching and mentoring in the effective altruist movement.